The present invention generally relates to scroll compressors and, more particularly, to apparatus and methods reducing vibration in scroll compressors.
To save weight, power consumption, and cabin heat load, large passenger airliners are using centralized vapor cycle systems to cool food, drink, and in some instances, avionic electronic components. To enable load matching with the large variation in heat load demand and variation of climates due to airport locations and fly altitudes, variable compressors with wide operating speed band are employed.
An Oldham ring is used to keep the orbiting scroll from rotating. The Oldham ring is in an oscillating motion, along a single axis, at the same frequency as the orbiting scroll motion and compressor motor rotation. The Oldham ring motion is unbalanced and produces an unbalance force that is a function of the square of the compressor speed. The unbalance force is in a sine wave form with a frequency equal to the compressor operating speed.
At high compressor speed, the Oldham ring unbalance force creates vibration force that can transmit into the aircraft structure and into the passenger cabin. The transmitted vibration can cause extra noise in the cabin environment and be a passenger comfort issue.
Methods to reduce vibration transmission include vibration isolators and vibration dampers. Wide compressor operating speed band reduces some of the effectiveness of isolators and dampers.
As can be seen, there is a need to minimize vibration from scroll compressors.